“Kanban” is a Japanese term that means signal. Kanban is one of the primary tools of a just-in-time manufacturing system (meaning a planning system for manufacturing processes that optimizes availability of material inventories at a manufacturing site to only what, when and how much is necessary). Kanban signals a replenishment process for production and materials, and maintains a generally orderly and efficient flow of materials throughout a manufacturing process. Kanban may be implemented via a printed card that contains specific information such as item name, description, quantity, etc.
Kanban control cycles define a replenishment process in terms of operational states. A Kanban control cycle can be characterized as a sequence of different operational states. Kanban control cycles occur between a supplier and a consumer, i.e., the one replenishing an item and the one requesting that the item be replenished, respectively. The item can be any kind of material, such as a component or an assembly, that needs to be replenished. In a Kanban control cycle, a signal indicating that the material needs to be replenished is sent from the customer to the supplier. This signal, called the Kanban, may be part of an electronic message or an actual physical device, such as a card. The operational state of the Kanban may be modified to provide item-related information, as described below.
By way of example, a material may be needed by a consumer for use in a machine or process. As a result of this need, an operational state of the Kanban is set from “full” to “empty”. The consumer therefore sends a Kanban to a supplier instructing the supplier to provide more of (e.g., a specified amount of) the material. In this example, the Kanban identifies the material, the amount of the material, and the consumer. After the Kanban arrives at the supplier, the supplier processes the order and sends the material to the consumer. The state of the Kanban is then changed from “empty” to “full”.
States of a Kanban correspond to states of a cycle that is performed to replenish an item. Electronic Kanban systems associate a state change of a Kanban with related electronically-controlled actions, such as printing Kanban cards, visualizing replenishing scenarios, creating and sending replenishment orders (e.g. electronically transmitting a purchase order to a supplier), and updating inventory levels.
Existing Kanban control cycles operate on an item-by-item basis, making it difficult to address more than one item at a time. This can be problematic, particularly in situations, such as supply chains, where the supply of one item depends on the supply of another item.